2018/07/31 by Vincent Van Eylen, Simon Albrecht, Chelsea X. Huang +13 · 248 citations
Physics and Astronomy · #Astro and Planetary Science #Astrobiology #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Eccentricity (behavior) #Orbital mechanics #Physics #Planet #Stellar, planetary, and galactic studies #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/aaf22f
published in The Astronomical Journal 157(2), 61 (Institute of Physics) · Accepted for publication in The Astronomical Journal
arxiv created 2018/11/18 · openalex publication_date 2019/01/21 · arxiv updated 2019/01/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Abstract We determine the orbital eccentricities of individual small Kepler planets, through a combination of asteroseismology and transit light-curve analysis. We are able to constrain the eccentricities of 51 systems with a single transiting planet, which supplement our previous measurements of 66 planets in multi-planet systems. Through a Bayesian hierarchical analysis, we find evidence that systems with only one detected transiting planet have a different eccentricity distribution than systems with multiple detected transiting planets. The eccentricity distribution of the single-transiting systems is well described by the positive half of a zero-mean Gaussian distribution with a dispersion σ e = 0.32 ± 0.06, while the multiple-transit systems are consistent with . A mixture model suggests a fraction of of single-transiting systems have a moderate eccentricity, represented by a Rayleigh distribution that peaks at . This finding may reflect differences in the formation pathways of systems with different numbers of transiting planets. We investigate the possibility that eccentricities are self-excited in closely packed planetary systems, as well as the influence of long-period giant companion planets. We find that both mechanisms can qualitatively explain the observations. We do not find any evidence for a correlation between eccentricity and stellar metallicity, as has been seen for giant planets. Neither do we find any evidence that orbital eccentricity is linked to the detection of a companion star. Along with this paper, we make available all of the parameters and uncertainties in the eccentricity distributions, as well as the properties of individual systems, for use in future studies.